code: def log_cmap(
      field_name: str,
      palette: Sequence[ColorLike],
      low: float,
      high: float,
      low_color: ColorLike | None = None,
      high_color: ColorLike | None = None,
      nan_color: ColorLike = "gray",
  ) -> Field:
      """Create a ``DataSpec`` dict that applies a client-side ``LogColorMapper``
      transformation to a ``ColumnDataSource`` column.
  
      Args:
          field_name (str) : a field name to configure ``DataSpec`` with
  
          palette (seq[color]) : a list of colors to use for colormapping
  
          low (float) : a minimum value of the range to map into the palette.
              Values below this are clamped to ``low``.
  
          high (float) : a maximum value of the range to map into the palette.
              Values above this are clamped to ``high``.
  
          low_color (color, optional) : color to be used if data is lower than
              ``low`` value. If None, values lower than ``low`` are mapped to the
              first color in the palette. (default: None)
  
          high_color (color, optional) : color to be used if data is higher than
              ``high`` value. If None, values higher than ``high`` are mapped to
              the last color in the palette. (default: None)
  
          nan_color (color, optional) : a default color to use when mapping data
              from a column does not succeed (default: "gray")
  
      """
      return Field(
          field_name,
          LogColorMapper(
              palette=palette,
              low=low,
              high=high,
              nan_color=nan_color,
              low_color=low_color,
              high_color=high_color,
          ),
      )
  
file_path: bokeh/src/bokeh/transform.py
imports: from __future__ import annotations
  import logging
  from typing import TYPE_CHECKING, Sequence, Union
  from .core.property.vectorization import Expr, Field
  from .models.expressions import CumSum, Stack
  from .models.mappers import CategoricalColorMapper, CategoricalMarkerMapper, CategoricalPatternMapper, EqHistColorMapper, LinearColorMapper, LogColorMapper
  from .models.transforms import Dodge, Jitter
label_desc: Use image node_id 9 for calling a global function with example usage: log_cmap(field_name, palette, low, high, low_color, high_color, nan_color) and returns: Field